Product Review: Slime Tire Sealant

Can Slime out-perform the competition?

Sports Authority haul
Daniel Oines

There is nothing worse than a flat tire, or a leaking tire. For years I have used Fix-A-Flat to seal up problem tires but recently had a tire Fix-A-Flat couldn't handle. Someone suggested I try Slime, the green tire sealant. I wondered if Slime could perform where Fix-A-Flat could not. The difference is intriguing and points to the different abilities that each of these very usable products has. For example, Fix-a-Flat is a liquid that is injected simultaneously with its own supply of compressed air. Some people don't like using aerosol tire inflation products like this because they think the end result can be dangerous. While this hasn't been proven at all, the believers are out there, and nothing will make them use that can. Slime works differently in that the sealant (that green slimy stuff) is injected into the tire before the process of reinflation starts. After the right amount of Slime is injected into the tire through the normal tire fill valve, a small compressor is used to fill the tire up to correct operating pressure.


Real World Testing

I was skeptical that Slime Tire Sealant would work for this blown out tire. Unlike Fix-A-Flat that uses a propellant in the can to push the sealant into the tire, Slime used just the pressure of squeezing the bottle by hand. But then I looked closer and realized the folks at Slime came up with a better way to get the sealant into the tire. They provide a tool to get the center of the valve stem out so the Slime flows uninterrupted into the tire. You squeeze the whole bottle in and ever so often rotate the tire to get even distribution of the Slime. According to their website Slime relies on a "state-of-the-art blend of environmentally friendly fibers, binders, polymers and proprietary congealing agents which intertwine and clot within the puncture." Basically, they made the Slime with plenty of good stuff for fixing problem tires. The real question is did it work in this case -- where Fix-A-Flat failed -- and the answer is yes, the Slime outperformed the competition. This is now my new go-to tire sealant, I bought four bottles yesterday!

Since this test, we have been using Slime to seal tires on our vintage cars for years. It remains super easy to use and has been a reliable way to remedy flat tires on vintage cars and trucks. Like most sealants, the balance of the wheel is greatly affected by the Slime, so it's not usually great to use long term. That said, it is possible to have the Slime spread so evenly inside the tire that it can still be balanced properly by a professional tire shop with a top rate balancing machine. This hasn't been our direct experience, so we always recommend that people use the Slime tire sealant only to get them out of an emergency situation and only as long as is absolutely necessary. Driving a car with out of balance tires can cause all sorts of suspension problems over the long term. I'm talking about suspension problems that can cause you money, so you should be well motivated to avoid them. 

Car repair products are often about innovation, and when Slime hit the parts store shelves years ago, it was clear that, after years of very few new ideas in flat tire management, there was finally a game changer becoming available to the general public. It's not a perfect product, but it's added a new facet to this product realm, and with so few decent options for flat tires or leaky tire management, Slime is very often the only answer. Thankfully it's proven to be a good answer and the product has stood the test of time. Since it's available at every parts store, and most big box department stores, you can pick up a kit easily.